1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method for processing spectral image data of an object.
2. Description of the Related Art
An object can be recorded as an image relating to a spectral distribution or spectral reflectance by, for example, using a multiband camera with multiple filters that have different transmission wavelength regions. The multiband camera captures the object by using light passing through the multiple filters as discussed in Japanese Patent Application Laid-Open No. 2007-278950.
Further, as an image clustering method of the object (object image) based on the spectral distribution or spectral, for example, Japanese Patent Application Laid-Open No. 2005-39408 discusses a image clustering method relating to a person's skin.
According to this method, image clustering can be performed accurately even when division is impossible because the colors are considered to be the same with three primary colors red (R), green (G), and blue (B), for example. Furthermore, if image clustering of the object is performed accurately, image processing such as color processing and noise processing can be performed in an optimal manner for each area.
However, for image clustering based on spectral data using conventionally-known methods, the target object must be uniformly illuminated by a single illumination light source.
For example, when bright and dark areas are formed on the object due to the three-dimensional shape of the target object, the distribution of the obtained spectral data is different between the sun-lit area and the shadow area on that object. Therefore, conventionally, even if the areas have identical spectral reflectance, it is difficult to recognize these areas as the areas having the same spectral data.
Further, when the object is illuminated by a plurality of illumination light sources having different spectral radiances, it is similarly difficult to recognize areas, which are illuminated by different illumination light sources, as the same areas.